That There is the place you go to when you are just blacked-out drunk. It's when you are so drunk it's just plain stupid. This term will be most identifiable with college students and binge drinkers.
Ryan: Wow, Justin! You just tall poured 10 beers in a row. Are you getting hammered tonight.
Justin: Yeah, you know I'm a hoss. I'm gettin THAT THERE tonight. After this bottle of vodka, I will be THAT THERE.